[dia] Don't use deprecated macro GTK_CHECK_CAST.

[Hans Breuer <hans src gnome org>]

commit b42e540e58d674cd1325ba28cbdf70dcaa22e1da
Author: Adam Buchbinder <adam buchbinder gmail com>
Date:   Mon May 4 13:29:55 2009 -0400

    Don't use deprecated macro GTK_CHECK_CAST.
    
    Replaced GTK_CHECK_CAST with G_TYPE_CHECK_INSTANCE_CAST:
    http://library.gnome.org/devel/gtk/stable/gtk-Types.html#GTK-CHECK-CAST--CAPS
    
    Signed-off-by: Adam Buchbinder <adam buchbinder gmail com>
    Signed-off-by: Hans Breuer <hans breuer org>
---
 app/layer_dialog.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/app/layer_dialog.c b/app/layer_dialog.c
index a1ebfab..240568b 100644
--- a/app/layer_dialog.c
+++ b/app/layer_dialog.c
@@ -43,7 +43,7 @@
 
 /* DiaLayerWidget: */
 #define DIA_LAYER_WIDGET(obj)          \
-  GTK_CHECK_CAST (obj, dia_layer_widget_get_type (), DiaLayerWidget)
+  G_TYPE_CHECK_INSTANCE_CAST (obj, dia_layer_widget_get_type (), DiaLayerWidget)
 #define DIA_LAYER_WIDGET_CLASS(klass)  \
   GTK_CHECK_CLASS_CAST (klass, dia_layer_widget_get_type (), DiaLayerWidgetClass)
 #define IS_DIA_LAYER_WIDGET(obj)       \